Fastener driving apparatus



. A. wANDEL FAS TENER DRIVING APPARATUS April 6, 1965 Filed March 18,1963 \00 60 627%@ so es.

BY Mum, /falmmm @fm/m Arx/65% United States Patent O Y 3,176,592FASTENER DRXVHQG APPARATUS Gscar A. Wandel, Mundelein, iii., assigner toFastener Corporation, Franklin Park, lll., a corporation of IllinoisFiled Mar. 13,1963, Ser. No. 255,840 Claims.V (Cl. 91-457) Thisinvention relates to a fastener driving apparatus and, moreparticularly, to a fluid actuated device for driving fasteners into aworkpiece.

The present invention is an improvement on pneumatically actuatedfastener driving apparatus of the type disclosed in United States PatentNo. 3,043,272. in pneumatically actuated fastener driving apparatus ofthis type, it is desirable to provide a pneumatically actuated pistonreturn mechanism which eliminates many or all of the disadvantages ofthe previous types of apparatus having spring actuated piston returnmechanisms.

Accordingly, it is an object of the present invention to provide a newand improved iiuid actuated fastener driving apparatus, Y

Another object of the present invention is to provide a new and improvedmeans for supplying a pressurized iluid to a cylinder for driving apiston therein which carries a fastener driving blade.

Another object is to provide `a fastener driving tool including new andimproved means for exhausting fluid from a cylinder after a drivingstroke to permit the return of a piston in preparation for anotherdriving stroke.

Still another object of the present invention is to provide an exhaustvalve assembly for a cylinder in a pneumatic fastener driving tool inwhich the valve assembly is opened and closed by engagement. withamovable closure element for the cylinder.

A further object ofthe present invention is to provide a new andimproved fastener driving apparatus of the type described above which israpid and reliable in operation, easily manufactured and assembled,simple in construction, and easily. serviceable.

In accordance with these andY many other objects and advantages, anembodiment of the present invention comprises a housing forming achamber which is continuously supplied with a pressurized uid, such ascompressed air. Within the chamber, there is provided a cylinder havingan open end exposed to the pressurized iluid in the chamber. A piston isslidably mounted in the cylinder and carries a fastener driving blade atits lower end for driving a fastener into a workpiece.

A iluid actuated main valve means is provided adjacent the open end ofthe cylinder and is movable into and out of engagement with the open endforcontrolling communication between the upper orV open end of thecylinder and the chamber. Exhaust valve means are provided on thehousing adjacent the open end of the cylinder for controllingcommunication between the upper end of the cylinder and theV atmosphere.The exhaust valve is provided with an operator which is engaged by andmoved with the main valve to control the operation of the exhaust valve.

Upon actuation of the device, the main valve is pneumatically lifted outof engagement with the end of the cylinder to admit compressed airfordriving the piston and blade downwardly to drive the fastener into theworkpiece. The lifting of the main valve permits movement of the exhaustvalve operator to close the exhaust valve so that compressed airentering the upper end of the cylinder will not escape to theatmosphere.

In order to return the piston and` driving blade to its upper positionin preparation for another driving stroke, the main valve is closed-against the open end of the cylinder. During this movement, the mainvalve moves the lCe engaged exhaust valve operator to open the exhaustvalve allowing the air in the upper end of the cylinder to escape totheV atmosphere; This permits the compressed air acting on the lowersurfaces of the piston to return the piston and driver blade to theirnormal position.

Many other objects and advantages of the present invention will becomeapparent from the following detailed description when considered inconjunction with the drawings, in which:

FIG. 1 is a fragmentaryY sectional view of a pneumatically operatedfastener driving apparatus embodying the present invention;

FIG. 2 ris a sectional view taken substantially along line 2 2 of FiG.1; v

FIG. 3a is an enlarged fragmentary sectional'view of an exhaust valvemeans included in the apparatus of FIG. l shown in an open or normalposition; and i FIG. 3b is a view similar to FIG. 3a illustrating theexhaust valve means in its closed position. i

Referring now more specifically to the drawings, therein is shown apneumatically operated fastener driving apparatus, referred to generallyas 10, which includes a housing 12 defining a chamber 14 continuouslysupplied with compressed air. Within the chamber 14, there is provided acylinder 16 having an enlarged upper section 18 terminating in an openupper end Ztl anda smaller diameter lower section 22 mounted in thelower end of the housing 14. An O-ring 24 is provided to prevent theleakage of air from the chamber 14 through a bottom wall 26 of thehousing 12 around the lower section 22 of the cylinder. The chamber 14is in continual communication with the middle portion of the cylinder 16by means of a ring of ports 28 positioned at the junction ofthe uppersection 18 and the lower section 22 of the cylinder; Within the cylinder16, there is provided a slidably mounted piston assembly 30 having agenerally radially extending upper piston portion 32 which slides in theupper section 1S and a generally radially extending lower piston portion341'- which slides in the section 22 of the cylinder 16. The pistons 32and 34 are integrally joined by a central portion 36 of considerablysmaller crosssection than either of the pistons forming a central cavity38 in the piston assembly 3i) which is in continual communication withthe chamber 14 by means of the ports 2S in the wall of the cylinder 16.

The piston portion 32 is provided with an O-ring 42 to seal the cavity38 from the upper end of the cylinder `16 above the piston portion 32,and the lower piston :portion 34 is provided with a similar O-ring 44Vto seal the cavity from the lower end of the cylinder below the pistonportion 32. The lower end of the piston assembly 3Q is provided with aresilient bumper stop 46 which strikes the lower wall 26 of the housingand absorbs the shock of the driving stroke.

lIn order to drive a fastener as the piston assembly 30 moves rapidlydownwardly on its driving stroke, there is provided a fastener driverblade 48 Whichis secured to the lower portion of the piston Vassembly bymeans of a pin 50 and an annular retaining ring 52. The lower wall 26 ofthe housing is provided with apertures 54 to allow fthe driver blade 48to pass therethrough and to allow air to pass freely from the atmosphereinto the lower section 22 of the cylinder below the piston portion 34. f

In accordance with one of the features of the present invention, thereis provided adjacentthe upper open end of the section 18 of the cylindera Yiiuid actuated main valve assembly 56 which includes a flexiblediaphragm 5S movable into andV out of engagement with the open end 2t)of the cylinder to control the communication between the chamber 14 andthe upper end of the section 18 of the cylinder 16. The diaphragm 58 issealingly secured between the upper end of the housing 12 and a `arecessed annular shoulder 70 formed in the cap piece 60 adjacent theupper end of the cavity 64. A locking and sealing O-ring 7-2 is providedto secure the disk 66 in place and prevent leakage of air into or out ofthe chamber 64 around the edges of the disk. The central aperture 68 ofthe disk is providedrwith an O-ring 74 to slidably `and sealingly engage`a depending stem 76 of a piston valve assembly 78. The lower `end ofthe stem '76 is threaded and provided with a shoulder 80 in order toaccommodate the diaphragm 58 and a stiifener 82 adjacent the uppersurface thereof and a stilener 84 adjacent the lower surface thereof.The diaphragm 58 and stitieners 82 and 84 are secured on the threadedportion of the stem 76 against the shoulder 80 by a nut 86, and a sealis provided between this diaphragm and the stem 76 by an Caring 88. Thussecured, the piston valve assembly 78 will move up and down with thediaphragm 58 of the main valve 56.

In order to accommodate the movement of the piston valve assembly 78,there is provided in the cap piece 60 another chamber-90 which isconcentrically located above the chamber 64 and separated therefrom bythe disk 66. The piston valve assembly 78 is provided with a radiallyextending flange or piston 92, `and theedge of this piston is providedwith an O-ring 94 which sealingly engages the side walls of the chamber90 as the assembly 78 moves up and down. The upper surface of the disk66 is provided with an annular cavity 96 which is vented to theatmosphere by means of a drilled passage 98 in the cap piece 60. Thus,the lower surface of the piston 92 iS always subject to atmosphericpressure regardless of its position in the chamber 90. The upper surfaceof the piston 92 is provided wi-th an annular recess 100 which iscontinuously in communication with an annular recess 102 provided in theupper wall surface .of the chamber 90. l y

The recess 102 is placed in communication with the chamber 64 in the cappiece 60 by a drilled passage 164 which comunicates with the chamber 64through a port- 106 in the side wall thereof. The passage 104 is also incommunication with a passageway 108 which runs from the cap piece 68through a hole in the diaphragm 58 and a land portion 110 formed in thehousing 12 within the chamber14 to a trigger valve assembly 112. Thetrigger valve assembly -112 is supported within a cylindrical well 114formed in the housing 12 and is secured therelin by a set screw 116. lAtrigger 11S pivotally mounted on the housing 12 provides means formanually actuating the valve assembly 112.r The passageway 108 extendsthrough the wall of the well 114- and is aligned with a side port 120which communicates with acentral valve chamber 122 of the assembly.

The chamber 122 is provided with an upper annular valve seat `124 vand alower annular valve seat 126. The upper seat 124 encircles a supply port128 which communicates with the interiorvof the housing 12 to supplycompressed air therefrom to the valve chamber 122., and the lower seatencircles an exhaust port 130 which communicates between the valvechamber 122 and the atmosphere. `Within the valve chamber there is`provided a movable valve member. 132 which alternately seats againstthe upper and lower seats 124 and 126 but which is normally biased toremain seated against the lower seat Vto allow compressed air from theinterior of the housing 12 to flow through the supply port 128 into thevalve chamber 122 and out through'the pasageway 108 to the chambers 64and 90.

The valve member 132 is provided with a depending valve stem 134 whichis normally biased downwardly by means of a spring 136 acting against awasher 138 secured to the stem. A lost motion mechanism 140 includes acontact button 142 engaging the trigger 118. vWhen the trigger isactuated, the valve member 132 moves upwardly and seats against theupper` seat y1=24 momentarily and then returns to seat on the lower seat126 even though the trigger is held in the depressed condition. Thus, inorder to initiate successive power strokes, the trigger 1118 must bereleased each time and then depressed.

An additional feature of the present invention is the provision of a newand improved exhaust valve assembly 142 which is carried on a landportion 144 formed in the housing wall adjacent the upper open end 20 ofthe cylinder 16. The assembly 142 includes a drilled valve chamber 146with an open upper end communicating with the chamber 14 and a blindlower end. A passage '-148 which extends between Ythe exterior of thehousing 12 and the interior of the upper section 18 of the cylinder 16adjacent the open end 20 also passes through the chamber 146. A valvemember 150 is slidably mounted within the chamber 146 and includes anoperating stem 152 extending upwardly therefrom and terminating in a cap154 of greater diameter than the chamber 146 to limit the downwardmovement thereof. A recessed shoulder 156 is provided at the open end ofthe chamber 146 to accommodate the cap 154 when it is in its downwardposition (FIG. 3a) so that it will not interfere with the closing of thediaphragm 58 against the open end 20 of the cylinder.Y The member 150 isprovided with an annular groove 158 which is located thereon at a properposition to provide a free flow of air from the upper end of thecylinder 16 to the atmosphere when the exhaust valve assembly 142 is inits normal or open position of FIG. 3a and to prevent communicationbetween the upper end of the `cylinder 16 and the atmosphere when theexhaust valve is in the operated position shown in FIG. 3b. A biasspring160 is provided in the blind end of the chamber 146 to urge the valvemember upwardly -so that the cap 154 engages the lowergsurface of thediaphragm 58. Thus, when the diaphragm moves downwardly as in FIG. 3a,the spring is compressed and the exhaust valve assembly 142 is opened tovent the upper end of the cylinder 16 to the atmosphere. When thediaphragm 58 moves upwardly to the position of FIG. 3b to open thecylinder 16, the exhaust valve assembly 142 closes to preventcommunication between the upper end of the cylinder 16 and theatmosphere.

The operation of the fastener driving apparatus 10 is eiiicient,reliable, and automatic. When a compressed air source is connected tothe housing 12, the interior thereof and the chamber 14 is pressurized,and compressed air ows into the central cavity 38 of the piston assembly30 resulting in an upward movement thereof because of the .difference inthe cross-sectional areas of the piston portions 32 and 34. Compressedair also ows throughv the supply passage 128,the valve chamber 122,

the passage of the trigger valve assembly 112, and the passageway 108into the chamber 64 through the port 106 and into the chamber 90 throughthe passage 104. This Vresults in a downward force on the piston valveassembly Yis firmly seated against the top or open upper end 20 of thecylinder. As the diaphragm 58 moves downwardly, it engages the cap 154to move the valve member 150 downwardly against the action of the springto the position shown in FIG. 3a. This opens the exhaust valve assembly142 to vent the upper end of the cylinder 16 to the atmosphere to `allowthe upwardly directed forces acting on the piston assembly 30 to movethe assembly to its uppermost position.

It should be noted that the upper surface of the piston portion 32 ofthe assembly 30 is relieved to accommodate the lower part of the stem 76and nut S6 on the piston valve assembly. Also since the passage 148 ispositioned below the top end 20 of the cylinder, a small `amount of airwill be trapped in the upper end of the cylinder as it moves to itsuppermost position. This trapped air is useful in providing a cushionedstop to the upward travel of the piston assembly but is not ofsufficient magnitude to unseat the diaphragm 58 from the open end 20 ofthe cylinder. In addition, the air within the chamber 90 below thepiston 92 is forced out of the passage 98 as this piston movesdownwardly to seat the diaphragm 58.

The operation just described is very rapid and the apparatus is nowready for operational use in driving a fastener. When the operatordepresses the trigger 118, it causes the valve member 132 to be movedupwardly to seat against the upper vvalve seat 124 spaced from the lowervalve seat 126. Thus, air pressure in the chambers 64 and 90 is ventedto the atmosphere through the passages 104 and 108, the valve chamber122, and the exhaust passage 130. When this happens, the air pressure inthe chamber 14 acting on the exposed lower side of the diaphragm 58lifts the diaphragm away from the open end of the cylinder 16. Since thechamber 14 completely surrounds the upper end of the cylinder 16 exceptfor the lands 144 and 110 (FIG. 2), the air ow into the cylinder israpid, and the piston assembly 30 is forced rapidly downward. As thediaphragm 58 moves away from the open end 20 of the cylinder to theposition shown in FIG. 3b, the valve spring 160 urges the valve member150 upwardly to the closed position preventing loss of the air enteringthe upper end of the cylinder 16 to the atmosphere through the passage148.

As the piston assembly 30 moves rapidly downwardly on the drivingstroke, the blade 48 engages and drives a fastener. The termination ofthe power stroke of the piston 30 is cushioned by the resilient bumper46 striking the bottom wall 26.

Because of the lost motion mechanism 140 previously described, the valvemember 132 is only momentarily seated against the upper seat 124 andthen returns to become seated on the lower seat 126 independent of therelease of the trigger 118. When this happens, compressed air fromwithin the housing 12 again flows into the chambers 64 and 90 throughthe supply port 128, the Valve chamber 122, the port 120, the passageway108, the port 106, and the passage 104. This compressed air acts againstthe upper surface of the piston valve 92 and the upper surface of thediaphragm 58 to force the diaphragm downwardly into engagement with theopen end 20 of the cylinder 16. The total downwardly directed force onthe diaphragm 58 is much greater than the upwardly directed forcethereon exerted by the air in the chamber 14. Consequently, the mainvalve assembly 56 closes rapidly.

As this happens, the valve member 150 is again moved downwardly to openthe exhaust valve assembly 142 (FIG. 3a) so that the upper port of thecylinder 16 is vented to the atmosphere. Since the effective lower areaof the piston portion 32 is greater than the upper area of the pistonportion 34, the compressed air admitted through the ports 28 provides anupwardly directed force on the assembly 36 for returning this assemblyto its normal upper position. During this return stroke, the airentrapped in the upper end of the cylinder 16 is discharged through theexhaust valve assembly 142. As the piston portion 32 passes the passage148 in the wall of the cylinder section 18, the remaining air above thepiston portion 32 is trapped and serves as a cushion to stop the upwardmovement of the piston assembly 30. The apparatus 10 is now ready todrive another fastener.

Although the present invention has been described with reference to asingle embodiment thereof, it should be understood that numerous othermodifications and embodiments can be devised by those skilled in the artthat will fall within the spirit and scope of the principles of thisinvention.

What is claimed as new and desired to be secured by Letters Patent ofthe United States is:

l. A fastener driving apparatus comprising a housing forming a chambercontinuously supplied with a pressurized uid, cylinder means in saidchamber having an open endexposed to the pressurized lluid in saidchamber, iluid actuated main valve means movableV downwardly into andupwardly out of engagement-with theV open end of said cylinder means forcontrolling communication between the open end of the cylinder means andthe chamber, vent passage means formed in the side walls of said chamberand said cylinder means below the open end thereof and communicatingbetween the interior y of the upper end of said cylinder means and theatmos-V phere,`and an exhaust valve means mounted in said vent passagemeans for Opening and closing communication in said vent passage meansbetween the upper end of the cylinder means and the atmosphere, saidexhaust valve means including an operator stem biased to extend upwardlyabove said open end to close said exhaust valve means when said mainvalve means is open adapted to be engaged by and moved downwardly by themain valve means to operate open the exhaust valve means when said mainvalve means closes the open end of said cylinder means.

2. A fastener driving apparatus as described in claim l wherein saidexhaust valve means includes a valve passage having an upper end incommunication with said chamber, a piston valve member slidable in saidvalve passage to open and close said vent passage means and biasingmeans in said valve chamber `for normally upwardly biasing said pistonvalve member to a closed position.

3. A fastener driving apparatus comprising a housing forming a rstchamber continuously supplied with a pressurized uid, cylinder means insaid first chamber having an open end exposed to the pressurized fluidin said first chamber, iluid actuated main valve means including aflexible diaphragm having a lower surface movable into and out ofengagement with the open end of said cylinder means for controlling thecommunication between the cylinder means and said first chamber, secondchamber means defined in said housing having a piston means slidablymounted therein, means connecting said piston means and said diaphragmfor moving the two in unison, means for selectively supplying thepressurized Huid to said second chamber -above said piston means and theupper surface of the diaphragm to move said diaphragm into and out ofengagement with the open end of said cylinder means, exhaust valve meansmounted on said housing for controlling communication between the upperend of said cylinder means and the atmosphere and including operatormeans engageable by and movable with said main valve means to open saidexhaust valve means when said main valve means engages the open end ofsaid cylinder means, and means for biasing said exhaust valve means toclose when the main valve means is away from the open end of saidcylinder means.

4. A fastener driving apparatus comprising a housing defining a firstchamber having an upper end and adapted Y to receive a compressed fluid,a cylinder in said rst chamber having an open upper end adjacent theupper end of said rst chamber, a piston movably mounted in saidcylinder, a movable diaphragm secured to the upper end of said firstchamber and movable toward and away from the upper end of said cylinderto close and open, respectively, communication between the upper end ofsaid cylinder and said first chamber, a second chamber in said housingadjacent the upper end of said iirst Vchamber having its lower wallformed by said movable diaphragm, a third chamber in said housingVadjacent said second chamber, piston means slidably mounted in saidthird chamber, means interconnecting said piston means and saiddiaphragm, first passage means in said housing venting the lower end ofsaid third chamber to the atmosphere, second passage means in saidhousing interconnecting the upper end of said third chamber above saidpiston means to the second chamber, exhaust valve means in said housingadjacent the upper end of said cylinder for venting the cylinder to theatmosphere, said exhaust valve means including an operator actuated bysaid diaphragm to open said exhaust valve means when said diaphragm isclosed against the` upper end of said cylinder and to close said exhaustvalve Vmeanswhen said diaphragm is away from said cylinder, and controlvalve means for selectivelyA connecting the second and third chambers tothe pressurized fluid and the atmosphere.

5. A fastener driving apparatus comprising a housing forming a irstchamber continuously supplied with a pressurizeduid, cylinder means insaid rst chamber having an open end exposed to the pressurized iluid insaid iirst chamber, iluid actuatedV main valve means in- 8 cluding aflexible diaphragm having a lower surface -movable into and out ofengagement with the open end of the cylinder means for controlling thecommunication bet-Ween the cylinder means and said rst chamber, secondchamber means delined in'said housing having a References Cited by theExaminer UNITED STATES PATENTS 3,043,272 7/62 'Wandel 91--420 3,081,7423/63 Goldring 91-454 3,106,134 10/63 Osborne 91-454 3,106,136 10/63Langas 91-461 FRED E. ENGELTHALER, Primary Examiner. SAMUEL LEVINE,Examiner.

1. A FASTENER DRIVING APPARATUS COMPRISING A HOUSING FORMING A CHAMBERCONTINUOUSLY SUPPLIED WITH A PRESSURIZED FLUID, CYLINDER MEANS IN SAIDCHAMBER HAVING AN OPEN END EXPOSED TO THE PRESSURIZED FLUID IN SAIDCHAMBER, FLUID ACTUATED MAIN VALVE MEANS MOVABLE DOWNWARDLY INTO ANDUPWARDLY OUT OF ENGAGEMENT WITH THE OPEN END OF SAID CYLINDER MEANS FORCONTROLLING COMMUNCIATION BETWEEN THE OPEN END OF THE CYLINDER MEANS ANDTHE CHAMBER, VENT PASSAGE MEANS FORMED IN THE SIDE WALLS OF SAID CHAMBERAND SAID CYLINDER MEANS BELOW THE OPEN END THEREOF AND COMMUNICATINGBETWEEN THE INTERIOR OF THE UPPER END OF SAID CYLINDER MEANS AND THEATMOSPHERE, AND AN EXHAUST VALVE MEANS MOUNTED IN SAID VENT PASSAGEMEANS FOR OPENING AND CLOSING COMMUNICATION IN SAID VENT PASSAGE MEANSBETWEEN THE UPPER END OF THE CYLINDER MEANS AND THE ATMOSPHERE, SAIDEXHAUST VALVE MEANS INCLUDING AN OPERATOR STEM BIASED TO EXTEND UPWARDLYABOVE SAID OPEN END TO CLOSE SAID EXHAUST VALVE MEANS WHEN SAID MAINVALVE MEANS IS OPEN ADAPTED TO BE ENGAGED BY AND MOVED DOWNWARDLY BY THEMAIN VALVE MEANS TO OPERATE OPEN THE EXHAUST VALVE MEANS WHEN SAID MAINVALVE MEANS CLOSES THE OPEN END OF SAID CYLINDER MEANS.